58-Ce-140
58-Ce-140 JNDC,JAERI EVAL-Mar90 JNDC FP ND W.G.,T.Nakagawa
DIST-MAR02 Rev3-Feb02 20020208
----JENDL-3.3 MATERIAL 5837
-----INCIDENT NEUTRON DATA
------ENDF-6 FORMAT
HISTORY
84-10 Evaluation for JENDL-2 was made by JNDC FPND W.G.[1]
90-03 Modification for JENDL-3 was made[2].
93-10 JENDL-3.2 was made by JNDC FPND W.G.[3]
***** Modified parts for JENDL-3.2
(2,151) Resolved resonance parameters
02-02 Modification was made by T.Nakagawa
***** Modified parts **************************************
(2,151) RRP
(3,1),(3,2),(3,4),(3,16),(3,51-91),(3,102)
All of MF04 and MF05
***********************************************************
MF = 1 General information
MT=451 Comments and dictionary
MF = 2 Resonance parameters
MT=151 Resolved and unresolved resonance parameters
Resolved resonance region (MLBW formula) : below 200 keV
For JENDL-2, the resonance parameters were evaluated by
Kikuchi[4]. Neutron widths were obtained from data measured
by Hacken et al.[5] and Camarda [6], and radiation
widths from capture areas by Musgrove et al.[7] For the
resonances only whose capture area was measured, the neutron
width was deduced by assuming the average radiation width of
0.034+-0.029 eV for s-wave resonances and 0.029+-0.008 eV for
p-wave ones. A negative resonance was added so as to
reproduce the capture cross section of 0.57+-0.04 barn and
the elastic scattering cross section of 2.83+-0.11 barns at
0.0253 eV[8].
For JENDL-3.2, neutron widths of 14 resonances were replaced
with experimental data obtained by Ohkubo[9] in the energy
range from 2.5437 keV to 55.113 keV. Parameters of the
negative resonance were re-adjusted to the above thermal cross
sections [8].
For JENDL-3.3, neutron widths of 2.5- to 55- keV levels were
modified on the basis of Ohkubo et al. [10]. Capture widths
of all levels were multiplied by a factor of 1.4 so as to be
consistent with a new capture cross section measurement[11].
A negative level was modified and 1/v corresction was aplied
to the capture cross section.
No unresolved resonance parameters are given.
Calculated 2200-m/s cross sections and res. integrals (barns)
2200 m/s res. integ.
total 3.453 -
elastic 2.883 -
capture 0.570 0.344
MF = 3 Neutron cross sections
Below 200 keV, resonance parameters were given.
Above 200 keV, the spherical optical and statistical model
calculation was performed with CASTHY[12], by taking account of
competing reactions, of which cross sections were calculated
with PEGASUS[13] standing on a preequilibrium and multi-step
evaporation model. The OMP's for neutron given in Table 1 were
determined so as to reproduce the total cross section measured
by Camarda et al.[14] The OMP's for charged particles are as
follows:
Proton = Perey[15]
Alpha = Huizenga and Igo[16]
Deuteron = Lohr and Haeberli[17]
Helium-3 and triton = Becchetti and Greenlees[18]
Parameters for the composite level density formula of Gilbert
and Cameron[19] were evaluated by Iijima et al.[20] More
extensive determination and modification were made in the
previous work [2]. Table 2 shows the level density parameters
used in the calculation. Energy dependence of spin cut-off
parameter in the energy range below E-joint is due to Gruppelaar
[21].
MT = 1 Total
Spherical optical model calculation was adopted.
MT = 2 Elastic scattering
Calculated as (total - sum of partial cross sections).
MT = 4, 51 - 91 Inelastic scattering
Spherical optical and statistical model calculation was
adopted. The level scheme was taken from Ref.[22].
No. Energy(MeV) Spin-parity DWBA cal.
GR. 0.0 0 +
1 1.5962 2 + *
2 1.9033 0 +
3 2.0833 4 +
4 2.1079 6 +
5 2.3479 2 +
6 2.3498 5 +
7 2.4120 3 +
8 2.4641 3 - *
9 2.4809 4 +
10 2.5158 4 +
11 2.5214 2 +
12 2.5472 1 +
13 2.6289 6 +
14 2.8997 2 +
15 3.0011 2 +
16 3.0168 0 +
17 3.040 3 -
18 3.1186 2 +
19 3.226 0 +
20 3.2558 5 -
21 3.3204 2 +
22 3.331 4 +
23 3.3947 4 -
24 3.3951 4 +
Levels above 3.4246 MeV were assumed to be overlapping.
For the levels with an asterisk, the contribution of direct
inelastic scattering cross sections was calculated by the
DWUCK-4 code[23]. Deformation parameters (beta2 = 0.1012 and
beta3 = 0.127) were based on the data compiled by Raman et
al.[24] and Spear[25], respectively.
MT = 102 Capture
Spherical optical and statistical model calculation with
CASTHY was adopted. Direct and semi-direct capture cross
sections were estimated according to the formula of Benzi
and Reffo[26] and normalized to the capture cross section
mesured by Bergqvist et al.[27]
The gamma-ray strength function (5.73E-06) was adjusted to
reproduce the capture cross section of about 4.7 mb at 500 keV
measured by Harnood et al.[11]
MT = 16 (n,2n) Cross Section
MT = 17 (n,3n) Cross Section
MT = 22 (n,n'a) Cross Section
MT = 28 (n,n'p) Cross Section
MT = 32 (n,n'd) Cross Section
MT =103 (n,p) Cross Section
MT =104 (n,d) Cross Section
MT =105 (n,t) Cross Section
MT =107 (n,alpha) Cross Section
These reaction cross sections were calculated with the
preequilibrium and multi-step evaporation model code
PEGASUS[13].
The Kalbach's constant K (= 247.8) was estimated by the
formula derived from Kikuchi-Kawai's formalism[28] and level
density parameters.
Finally, the (n,p) and (n,alpha) cross sections were
normalized to the following values at 14.5 MeV:
(n,p) 7.50 mb (measured by Teng Dan+[29])
(n,alpha) 4.60 mb (recommended by Forrest[30])
MF = 4 Angular Distributions of Secondary Neutrons
Legendre polynomial coefficients for angular distributions are
given in the center-of-mass system for MT=2 and discrete inelas-
tic levels, and in the laboratory system for MT=91. They were
calculated with CASTHY. Contribution of direct inelastic
scattering was calculated with DWUCK-4. For other reactions,
isotropic distributions in the laboratory system were assumed.
MF = 5 Energy Distributions of Secondary Neutrons
Energy distributions of secondary neutrons were calculated with
PEGASUS for inelastic scattering from overlapping levels and for
other neutron emitting reactions.
Interpolation of 22 (unit base interpolation) was adopted.
Table 1 Neutron Optical Potential Parameters
Depth (MeV) Radius(fm) Diffuseness(fm)
---------------------- ------------ ---------------
V = 45.36-0.342*En r0 = 1.307 a0 = 0.62
Ws = 9.763+0.4167*En rs = 1.280 as = 0.35
Vso= 7.0 rso= 1.307 aso= 0.62
The form of surface absorption part is der. Woods-Saxon type.
Table 2 Level Density Parameters
Nuclide SYST a(1/MeV) T(MeV) C(1/MeV) EX(MeV) Pairing
---------------------------------------------------------------
56-Ba-136 1.610E+01 6.500E-01 5.721E-01 6.928E+00 2.280E+00
56-Ba-137 1.645E+01 5.640E-01 5.394E-01 4.905E+00 1.580E+00
56-Ba-138 1.390E+01 7.200E-01 4.123E-01 7.233E+00 2.430E+00
56-Ba-139 2.022E+01 4.800E-01 5.326E-01 4.629E+00 1.580E+00
57-La-137 1.558E+01 6.210E-01 3.521E+00 4.624E+00 7.000E-01
57-La-138 1.450E+01 6.310E-01 7.202E+00 3.634E+00 0.0
57-La-139 1.380E+01 6.500E-01 1.653E+00 4.468E+00 8.500E-01
57-La-140 1.558E+01 5.900E-01 7.912E+00 3.425E+00 0.0
58-Ce-138 * 1.618E+01 5.580E-01 2.611E-01 5.011E+00 1.870E+00
58-Ce-139 1.374E+01 6.450E-01 9.282E-01 4.685E+00 1.170E+00
58-Ce-140 1.413E+01 6.541E-01 3.376E-01 5.852E+00 2.020E+00
58-Ce-141 1.714E+01 5.150E-01 7.134E-01 3.957E+00 1.170E+00
---------------------------------------------------------------
SYST: * = LDP's were determined from systematics.
Spin cutoff parameters were calculated as 0.146*SQRT(a)*A**(2/3).
In the CASTHY calculation, spin cutoff factors at 0 MeV were
assumed to be 6.125 for Ce-140 and 9.569 for Ce-141.
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